South Sudan has unveiled proposals to advance peace talks with Sudan, including billions of dollars in financial concessions.

For its part, Sudan offered a muted reaction, saying any financial deal must come after a security agreement is reached.

The two countries went to the brink of war in April, after failing to resolve issues on borders, oil and citizenship stemming from the South's independence last year.

South Sudan says it will pay more than previously offered to use Sudan's oil pipelines, which it needs to export southern oil. It also offered greater debt forgiveness and a cash transfer of more than $3 billion.

South Sudan's chef negotiator at peace talks in Ethiopia said the proposal is his country's final offer.

A spokesman for Sudan's delegation said the two sides must discuss border security before negotiating any oil deal.

The African Union is hosting the talks in Addis Ababa. Multiple rounds of AU-hosted talks between the two Sudans have produced almost no progress.

South Sudan also proposed that the United Nations and African Union organize a referendum by the end of this year to determine the status of the contested Abyei region.

Disputes over who was eligible to vote led to cancellation of a planned Abyei referendum in early 2011.